I have the Companion 5 (1.st series I guess, soon to be 10 years if I'm not mistaken). Works perfectly. But, I'm thinking of buying a pair of headphones for my computer also. Not expensive ones so Bose headsets are off the table.
But, I've seen a lot of different impedance ratings and which one is the correct one for the 3.5mm headphone-jack, what impedance is Bose Companion 5 at? AFAIK for best sound and richness it's important to match impedance of the headphones to the amplifier, in this case the Companion 5.
Thanks for your inquiry. The 3.5mm headphone-jack on the Companion 5 Multimedia Speaker System is intended to be an added feature for general-purpose headphone listening. Since headphone amplification is not this product's primary purpose, your requested specifications are not published nor available. That being said, our best recommendation is to make sure that your new headphones have a return policy. This way, you can try the headphones out with your Companion 5 speakers to make sure you are satisfied with the audio quality.